Copyright owners are in a constant battle against piracy of their media content. In the current digital world, high quality copies of digital content can be readily made and distributed without permission of the copyright owners. With the increasing availability of high definition video content and no or low compression audio content, the need to prevent unauthorized copies of audio and video content is greater than ever. In response to these needs, various digital rights management (DRM) techniques have evolved. DRM is a broad term that is used for various techniques used by copyright owners and authorized publishers to control access and restrict use of media content on associated electronic devices.
High-Bandwidth Digital Content Protection (HDCP) is a form of DRM that was developed by Intel Corporation and is widely used to control the delivery of audio and video media content from one electronic device to another. For HDCP, a source device is able to prevent or at least restrict the playback quality of otherwise high definition media content to DVD (Digital Video Disk) quality, or standard definition, when a destination device does not have an HDCP compliant media interface. Two common HDCP compliant media interfaces include the HDCP compliant High Definition Multimedia Interface (HDMI) and the HDCP compliant Digital Video Interface (DVI). When the destination device does have an HDCP compliant media interface, the high definition media content is generally encrypted by the source device and delivered to the destination device in a secure fashion.
For HDCP, the media interfaces of the respective source and destination devices are able to communicate with each other and play pivotal roles to ensure that the media content is protected. The media interface of the source device will authenticate the media interface of the destination device, and the respective media interfaces will exchange any necessary encryption information to facilitate encryption of the media content by the media interface of the source device, and decryption of the encrypted media content by the media interface of the destination device. Notably, this functionality is generally provided in the hardware at the media interfaces and not in the higher level control systems of the respective electronic devices. Other DRM techniques, such as the Advanced Access Content System (AACS), operate in a similar fashion.
Unfortunately, many audio and video processing and interface cards, which often provide the actual media interfaces for various types of electronic devices such as personal computers, DVD players, set-top boxes, digital video recorders, audio processors and receivers, video processors, televisions, monitors, projectors, and the like, do not comply with HDCP or other DRM techniques. The manufacturers of these processing and interface cards often do not incorporate DRM techniques due to increased processing overhead, increased complexity, licensing costs, liability, and the like. Even though the control systems of the electronic devices in which the processing and interface cards are located generally have the processing capability to provide the functionality of compliant media interfaces, the use of non-HDCP compliant processing and interface cards results in non-HDCP compliant electronic devices. Further, legacy products may not have interfaces that are compliant with current DRM requirements. As such, users of non-compliant electronic devices are unable to enjoy the higher resolution audio and video that would otherwise be available to them, if the processing and interface cards were HDCP compliant.
Accordingly, there is a need for a technique to allow a source device that has a DRM compliant media interface to securely deliver media content to a destination device that does not have a DRM compliant media interface without compromising the integrity of the media content.